Coincidently with the period in the mid 1800’s when the British canal system was being superceded by the rail roads, the traditional iron foundries began to produce more steel than iron using the 1856 process invented by Sir Henry Bessemer (1813-1898). The Bessemer process and its later refinements were able now to produce steel in large quantities and at a fraction of the old price. Cast steel is superior to iron in tensile strength. This quality in the steel form of iron meant that bridge builders could now achieve the spectacular bridge spans that we take for granted today. Steel rapidly became the metal of choice for all heavy construction purposes from railroads to ship building to sky scrapers from the second half of the 19th century right up into our time.
The fact that our iron bridges enjoyed such a brief moment of fame as innovators should be a point of pride. It is a good indication of the creative and entrepreneurial energy which was harnessed to create them. Their very success spawned their successors. In the beginning, the Industrial Revolution was based on iron and these audacious and pioneering bridges of their time were the first conspicuous demonstration of iron’s potential.
Our bridges have the further distinction of being the result of one of the first collaborations between empirical experience and scientific discovery as applied to industrial problem-solving. This innovative approach was first put into practice in England in the 18th century and has proved so successful that we can no longer imagine problem solving any other way. This was the true “revolutionary” aspect of The Industrial Revolution. This is the legacy of our bridges.
Now that you appreciate the historical significance of the iron bridges, do take a second look at them from yet another prospective. For me, these old iron bridges still have the edge on modern bridges in several other respects: in their intimacy of scale, in their still airy grace and flair, in their retained sense of audacity for their time. I love their precedence: that they were the first and provide the link with our era and all the previous eras back to the Clapper bridges of the Bronze Age.
It is my hope that you will enjoy seeking them out as much as I have. As you become familiar with them, you will begin to spot them everywhere and to notice their children and grandchildren in more modern bridges. They become familiar landmarks and beloved old friends, still modestly and faithfully fulfilling their original purpose some 230 years later with an aura of patriarchal serenity.